What is a true ultrasonic toothbrush? What are some brands of ultrasonic toothbrushes? How are ultrasonic toothbrushes, electric toothbrushes, and sonic toothbrushes classified?
1. What Is a True Ultrasonic Toothbrush? (Ultrasonic Toothbrush)
First of all, there is a difference between ultrasonic toothbrushes and sonic toothbrushes.
Ultrasonic waves are sound waves with frequencies higher than 20,000 Hz. They are highly directional and have strong penetrating power, but are inaudible to the human ear. Currently, determining whether a toothbrush is a true ultrasonic toothbrush primarily depends on two factors: whether it contains a special transducer inside the brush head that generates ultrasonic waves, and whether the vibration frequency specified by the manufacturer exceeds 20,000 Hz.
So, what does it mean for a toothbrush to have a vibration frequency greater than 20,000 Hz?
That means it vibrates 20,000 times per second (which translates to 1.2 million vibrations per minute). In the technical specifications of ultrasonic toothbrushes—which manufacturers often promote with “over-the-top” claims—there is a parameter describing the brush head’s vibration frequency. However, this parameter does not necessarily refer to the number of vibrations per second; in many cases, it actually refers to the number of vibrations per minute.
When shopping, many consumers glance at the label and see a number that appears to be over 20,000, but in reality, the actual figure is quite different. Only by dividing the vibration frequency listed in the brochure by 60 can you determine the actual frequency. For example, if a toothbrush is labeled with a vibration frequency of 31,000 times per minute, the actual vibration frequency of its brush head is only 517 Hz.
2. Genuine Ultrasonic Toothbrush Brands
Currently, making ultrasonic toothbrushes is relativelyEstablished brands include the U.S.-based Ultrasonex and the German company EMAG, among others,Other brands' Ultrasonic Toothbrush (e.g., Smilex, Ultreo®, and Megasonex®) However, it’s hard to find it anywhere in China, whether in stores or online.
The first ultrasonic toothbrush was named Ultima and later renamed Ultrasonex. It was patented in the United States and approved by the U.S. Food and Drug Administration as a household appliance in 1992. Early ultrasonic toothbrushes relied solely on ultrasonic technology, but a few years later, Ultrasonex introduced a model that also incorporated an electric motor, providing users with additional sonic vibrations.
Ultrasonex's parent company was acquired in 2008 and withdrew from the oral hygiene market.
Most electric toothbrushes marketed as "ultrasonic" are actually just ordinary sonic toothbrushes. Currently, there are two main criteria for determining whether a toothbrush is a true ultrasonic toothbrush: whether it contains a special transducer inside that generates ultrasonic waves, and whether the vibration frequency specified by the manufacturer exceeds 20,000 Hz.
3. Classification of Ultrasonic Toothbrushes, Electric Toothbrushes, and Sonic Toothbrushes
Electric toothbrushes can also be classified based on their vibration speed into standard electric toothbrushes, sonic toothbrushes, or ultrasonic toothbrushes.
If a toothbrush vibrates fast enough to produce a humming sound within the audible frequency range (20 to 20,000 Hz), it can be classified as a sonic toothbrush, although the frequency range for this type of toothbrush generally falls between 200 and 400 Hz, which equates to 12,000–24,000 oscillations, or 24,000–48,000 vibrations per minute.
Any electric toothbrush with a vibration frequency exceeding the audible range (20 kHz, or 24,000 vibrations per minute) can be classified as an ultrasonic toothbrush.
Summary: A true sonic toothbrush must operate at a frequency exceeding 20,000 Hz. Leading brands include the U.S.-based Ultrasonex and the German brand EMAG.
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